Solenoids are electromechanical devices often used to convert electrical energy into mechanical energy and particularly into short stroke mechanical motion. As such, solenoids are frequently utilized for actuating valves in response to an electrical signal. For certain applications, valves must be positively maintained in predetermined positions to control the flow of gas or fluid through the valve. A first solenoid may be powered to positively move a valve to one position and a second solenoid may be powered to positively move the valve member to a predetermined position and maintain it there until the second solenoid is de-energized and the first solenoid is energized to move the valve member back to the other position. In situations where the valve is to be retained in the actuated position for significant time periods without continuous power or a sustained control signal, latching mechanisms may be used to hold the valve one position or the other. A remotely controlled pneumatic latching valve may use two solenoids to change operational states, i.e., supply to delivery and delivery to exhaust. Momentary activation of one solenoid actuates the pneumatic latching valve to deliver supply air while momentary activation of the other solenoid actuates the pneumatic latching valve to exhaust the delivered air pressure.
While basically effective for its intended purpose, the above-described system configuration is problematic in that the use of two solenoids to change the state of the pneumatic latching valve is expensive and redundant. Also undesirable is the additional size, weight, and plumbing complexity commonly found in this type of system. Thus, while the self-latching solenoid actuated pneumatic valves known in the related art have are generally useful, there continues to be a significant need for smaller, less complicated, and less expensive pneumatic latching valves. Furthermore, especially in the case of vehicle braking systems, there continues to be a need for a latching valve that will not undergo a change of state if power to the solenoids is lost or interrupted.